This invention relates to an electronic toothbrush.
An electronic toothbrush well-known in the art includes a bristle portion and a handle the interior of which accommodates a battery, one electrode of which is connected to the bristle portion by a conductor. A conductor connected to the other electrode of the battery is secured to the surface of the handle. By grasping this conductor with the hand and bringing the bristles of the toothbrush into contact with the teeth, a current is caused to flow from the hand to the surface of the teeth through the human body.
When the handle of this conventional electronic toothbrush is grasped by the hand, approximately 50 to 100 .mu.A of current is produced and causes a positive current to flow through the human body. This in turn causes positive charges to accumulate on the high-protein plaque on the teeth. As a result, the positive current flowing through the teeth repulses the positive charges on the plaque, so that the plaque readily separates from the teeth and is attracted to the negative bristles of the toothbrush.
A problem with this conventional electronic toothbrush, however, is that the user can never be certain as to whether the current is truly flowing when the toothbrush is being used. The user therefore cannot be confident that the toothbrush is operating properly. Moreover, verifying that the current is flowing is a troublesome task.